Despite exhibiting increased metaphase figures, asp¹ mutant brains do not display neuroblast loss.

Transheterozygous asp^E3/asp¹ pharates present a striking reduction of the head size while abdomen and thorax seem unaffected.

87.8% of mitotic cells in Spc25^mitch-1/Df(3R)ry75 larval brains have overcondensed chromosomes, and the mitotic index is increased compared to wild type. The ratio of mitotic cells in prometaphase/metaphase to those in anaphase/telophase is greatly increased compared to wild type.

98.2% of the ovarioles of homozygous females do not produce eggs. 52.4% of egg chambers have the normal complement of germ cells and 47.5% of egg chambers contain fewer than 16 germ cells. The oocyte nucleus is sometimes missing and is occasionally mispositioned. 97.7% of the ovarioles of asp¹/asp^DD4 females do not produce eggs. 44.1% of egg chambers have the normal complement of germ cells and 55.9% of egg chambers contain fewer than 16 germ cells. The oocyte nucleus is sometimes missing and is occasionally mispositioned.

Spermatocytes in asp¹ homozygotes, asp¹/asp^DD4 trans-heterozygotes and asp¹/Df(3R)Hd^γ1 trans-heterozygotes display spindle abnormalities during meiosis I. In late prophase, the majority of spindles are irregular. In metaphase, approximately half of the spindles are irregular. These are defined as spindles exhibiting long and wavy microtubules and/or the absence of distinct bundles of kinetochore microtubules. In late anaphase and late telophase, approximately a third of spindles are irregular, with a proportion of spindles absent. In oocytes of asp¹/asp^DD4 trans-heterozygotes, meiosis I and II progress normally, however the sperm aster does not increase in dimension as in wild-type. In the asp mutant cytoplasm, the microtubules of the sperm aster never extend to the egg cortex. The sperm aster duplicates as in wild-type but is frequently found to detach from the spindle forming around the haploid male pronucleus.

Most dividing neuroblasts arrest in metaphase in homozygous larval brains. A substantial fraction of the metaphases show precocious centrosome splitting. The astral microtubules are generally shorter and fewer than in wild-type metaphases. Many spindle microtubules are poorly focused and do not appear to terminate at the centrosome. 41% of homozygous spermatids consist of a normal-sized nucleus associated with a normal Nebenkern. 15% contain a normal Nebenkern associated with an abnormally sized nucleus (probably the consequence of a failure in chromosome segregation but not in cytokinesis). 23% have 2 or 4 normal-sized nuclei associated with a single Nebenkern of 2 or 4 times the normal size (the consequence of a failure in cytokinesis but not in chromosome segregation). In addition, spermatids consisting of a single large Nebenkern associated with 2 (12%), 4 (3%) or more than 4 (6%) nuclei of different sizes are seen (probably a consequence of failures in both cytokinesis and chromosome segregation). Asters are smaller than normal during meiotic prometaphase in mutant males and are often not attached to the nuclear envelope (in contrast to wild type). The two asters are usually close to each other, suggesting a delayed migration to the opposite sides of the nucleus. Spermatocytes form abnormally shaped and poorly focused bipolar spindles. The centrosomes do not appear to be attached the ends of these spindles in many cells, but instead float free in the cytosol. Central spindle morphology looks normal in about half of the meiotic telophases in mutant males, but is severely affected in the other half of telophases. The central spindle fails to form completely in a fraction of the abnormal telophases, while in the remaining cells some interzonal microtubules can be discerned that are organised in small and irregular bundles that do not completely traverse the cell. Telophases with abnormal central spindles have a disrupted actin contractile ring.

Postmeiotic spermatogenic stages of asp¹ males show a series of alterations due to the abnormal meiotic spindles. The most conspicuous alterations include variable size nuclei and nebenkern of early spermatids. The spermatids are also multinucleate instead of having a single uniform size nucleus. The spermatids are elongated: abnormal size mitochondrial derivatives elongate alongside more than one axoneme. Some spermatids remain syncytial due to failure of the individualization process and are eliminated during the coiling stage.

asp¹ homozygous larval brains have a high mitotic index, extremely condensed X-shaped chromosomes and numerous aneuploid and polyploid cells: a fraction of the cells may continue to divide when the maternal gene product for spindle production is exhausted, and mistakes are made in chromosome segregation resulting in high frequencies of aneuploid and polyploid cells. In larvae carrying Df(3R)Su9 and Df(3R)L16 the brain phenotype is similar to asp¹ homozygous larvae except aneuploid and polyploid cells are rare and no anaphases are found. Adult escapers have an increase in cuticular defects similar to asp homozygote and male and female sterility. Does not interact with βTub85D.

In asp¹ homozygotes the mitotic cycle is arrested in metaphase resulting in a high frequency of polyploid cells. Sex chromosome disjunction during male meiosis is severely affected resulting in diplo and nullo gametes. The meiotic spindles of living cells are morphologically abnormal due to an altered structural component of the spindle other than the tubulins.

Most larvae with small or absent imaginal discs; delayed development; survivors with nicked wings and rough eyes. Males sterile at 18^oC and fertile at 25^oC; produce abundant MI nondisjunction. Larval neuroblasts frequently polyploid, especially when held at 18^oC. Phenotype enhanced by duplications for 97B. Enhanced by: Ts(Y;3Rt)B158 Not enhanced by: Ts(Y;3Rt)R71

asp¹ has meiotic telophase II & spindle phenotype, enhanceable by asl²

asp¹ has eye phenotype, enhanceable by rl¹

asp¹ has wing phenotype, enhanceable by rl¹

asp¹ has eye phenotype, suppressible by rl^Su14

asp¹ has wing phenotype, suppressible by rl^Su14

asp¹ has eye phenotype, suppressible by Dsor1^Su1

asp¹ has wing phenotype, suppressible by Dsor1^Su1

asp¹/asp[+] is an enhancer of embryonic/larval cuticle phenotype of baz⁴

asp¹/asp[+] is an enhancer of embryonic/larval cuticle phenotype of baz^G0484